Why do I need to practice? How long should I practice? What should I practice?

Whenever I bring up the subject of practice I see the student's eyes glaze over.

The purpose of practice is to develop reliable habits so that when you are required to perform you can conce...

Why learn to sing? You can either sing or you can't - right?  If I already have a beautiful voice, why do I need lessons? If my voice sucks, why would I bother?
The purpose of voice lessons is to optimise the process, improve the voice you have - (much like pol...